| 1 | FIR | First Line Air | | | ICAO1 |
| 2 | FIR | Flats Industrial R.R. Co. | 7/2000-7/2005 | | NAKINA |
| 3 | FIR | Flats Industrial R.R. Co. | Jul-00 | | NRHS |
| 4 | FIR | FLATS INDUSTRIAL RAILROAD | | | PWRC |
| 5 | FIR | Flats Industrial Railroad | | | RSRV |
| 6 | FIR | FLATS INDUSTRIAL RAILROAD COMPANY | | | SCAC4 |
| 7 | FIRC | FIRST TRANSPORTATION COMPANY | | | SCAC3 |
| 8 | FIRC | FIRST CONTINENTAL FREIGHT SYSTEMS | | | SCAC4 |
| 9 | FIRE | FIREPROOF STORAGE AND VAN COMPANY I | | | SCAC3 |
| 10 | FIRE | FIREMASTER OILFIELD SERVICES INC | | | SCAC4 |
| 11 | FIRE | Fire patrol | | X | TRAFFIC |
| 12 | FIRG | First Glasgow | | GB | TRAFFIC |
| 13 | FIRI | FISHER, R T INC | | | SCAC3 |
| 14 | FIRL | FIORILLO, RONALD TRUCKING | | | SCAC3 |
| 15 | FIRM | First Manchester | | GB | TRAFFIC |
| 16 | FIRN | FIRSTCO TRANSPORTATION LLC | | | SCAC4 |
| 17 | FIRQ | FIRST (1ST) LINE LOGISTICS | | | SCAC4 |
| 18 | FIRR | FIBER TRANSPORT | | | SCAC3 |
| 19 | FIRS | FLATS INDUSTRIAL RAILROAD COMPANY | | | PWRC |
| 20 | FIRS | FIRPO & SONS INC | | | SCAC3 |
| 21 | FIRT | FILM TRANSIT, INC | | | SCAC3 |
| 22 | FIRW | FAIRWAY INC | | | SCAC3 |
| 23 | FIRW | FAIRWAY INC | | | SCAC4 |
| 24 | FIRX | Federal Ice Refrigerating Co. | 7/1930 | | NAKINA |
| 25 | FIRX | FEDERAL ICE REFRIGERATING CO. | | | PWRC |
